During semiconductor wafer fabrication, patterned radiation can be produced in a lithographic process to enable formation of very small patterns, such as nanometer-scale patterns, on a semiconductor wafer. In extreme ultraviolet (EUV) lithography, for example, a pattern formed on an EUV lithographic mask can be transferred to a semiconductor wafer by exposing a resist layer formed on the semiconductor wafer to EUV light reflected off of portions of a reflective surface.
Due to the very short wavelengths (high frequencies) used in EUV and other high resolution lithographic techniques, the patterning radiation utilized is highly absorbed by many resist materials. In addition, the radiation sources relied upon in some techniques are of limited brightness, EUV light sources for example, further limiting the radiation dose available for lithographic patterning.
A conventional approach to compensating for low source brightness and the high absorbance of patterning radiation is to utilize a resist material including a photo-activated catalytic species, for example a photo-acid, to chemically amplify a latent image formed on the resist. However, unresolved difficulty in adequately controlling diffusion of photo-acids at very small dimensions limits the ability of chemically catalyzed patterning methods to capture the ever finer patterns being produced in EUV and other high resolution lithographic techniques.